Most modern passenger and military aircraft are powered by
gas turbine engines, which are also called
jet engines. Jet engines come in a variety
of shapes and sizes but all jet engines have certain parts in
common.

At the top of this slide we have a picture of a Pratt and Whitney
F100 jet engine, which is used in the F15 and F16 fighter aircraft.
As we can see in the picture, jet engines are complicated pieces of
machinery. Jets have a lot of parts which spin on a central shaft. To
enclose the spinning parts, a jet engine is shaped like a long
cylinder. At the bottom of the slide we have a much simpler computer
drawing of the engine parts. On the animated version of this slide
you can take the "computer" engine apart to look at the pieces and
see how they go together.

In the computer drawing, we have cut out a portion of the engine
to have a look inside. Various parts on the photograph are labeled
and the corresponding parts on the computer drawing are indicated. At
the front of the engine, to the left, is the inlet
which brings outside air into the engine. The F100 engine picture
does not show the aircraft inlet because the inlet is part of the
airframe and changes from aircraft to aircraft. At the exit of the
inlet is the compressor, which is colored
cyan. The compressor is connected by a blue colored shaft to
the turbine, which is colored magenta. The
compressor and the turbine are composed of many rows of small
airfoil shaped blades. Some rows are
connected to the inner shaft and rotate at high speed, while other
rows remain stationary. The rows that spin are called rotors
and the fixed rows are called stators. The combination of the
shaft, compressor and turbine is called the turbomachinery.
Between the compressor and the turbine flow path is the combustion
section or burner, which is colored red.
This is where the fuel and the air are mixed and burned. The hot
exhaust then passes through the turbine and out the nozzle.
The nozzle performs two important tasks.
The nozzle is shaped to
accelerate
the hot exhaust gas.
The nozzle is also used to set the
mass flow rate
through the engine. The
thrust equation
indicates that the change in velocity (acceleration) times the mass flow rate
determines the thrust of the engine.
The F100 is an afterburning turbofan engine
and the flame holders for the afterburner are shown in orange in the
nozzle of the drawing. (The front section of the F100 is the fan
section which is not modeled on the computer drawing.)

To analyze jet engine operation, engineers have adopted a
numbering scheme for the various parts. This scheme and the
accompanying two-dimensional schematic
drawing are given on a separate slide.

You can investigate the effects of the various engine parts on jet
engine operation by using the
EngineSim
interactive Java applet.
You can vary the performance of any of the engine parts and investigate
the effects on thrust and fuel flow.